Locking cap



FIG. 1 is a top perspective view of a locking cap, showing my new design;

FIG. 2 is a front elevational view thereof; and,

FIG. 3 is a side elevational view thereof.

Subject matter illustrated in dashed lines depicts environmental subject matter only and does not form part of the claim. 

The ornamental design for a locking cap, as shown and described. 